System for fixing a rail and adapter piece for such a system

ABSTRACT

A system for fixing a rail onto a foundation comprises a spring element, which can be clamped against a foundation by means of a clamping element, with at least one spring arm and an adapter piece. The adapter piece has a holder, in which an end section of the spring arm of the spring element sits, and a contact surface section formed at its periphery, with which, when the system is assembled, it sits on the rail foot of the rail to be fixed, such that the elastic retaining force exerted by the spring element is transferred onto the rail foot.

The invention concerns a system for fixing a rail, wherein this system has a spring element, which can be clamped against the foundation by means of a clamping element, which spring element has at least one spring arm, and an adapter piece, which has a holder, in which an end section of the spring arm of the spring element sits.

The invention also concerns an adapter piece provided for a system of this type.

An adapter piece used in a system according to the invention has a contact surface section formed at its periphery, with which, when the system is finally assembled, it sits on the rail foot of the rail to be fixed in order to transfer the elastic retaining force exerted by the spring element onto the rail foot.

A system of the type mentioned at the beginning is known, for example, from DE 20 2007 018 500 U1. In the known system, the adapter piece isolates the clamp, used there as a spring element, from the rail. For this purpose, the adapter piece is manufactured from an electrically non-conductive material. In order to allow a particularly simple assembly at the same time, the adapter piece in the known system has a holder, which is adapted to the shape of the end section allocated to the isolating clip such that the spring section can be inserted into it in form fit. The end section of the spring element concerned can therefore be inserted into the holder such that at least one segment of its periphery is surrounded by material of the adapter piece. In addition, the known adapter piece has a contact surface extending under the holder. This contact surface guarantees that the adapter piece is always guided such that the end section of the spring element engaging in its respective holder constantly remains in the holder concerned. In this way, the adapter piece can easily be slid from a pre-assembled position on the guide plate of the known system onto the rail foot, without manual intervention of a fitter or particular measures by an assembly machine being required in addition.

The fixing of rails subjected to high loads in practical use requires the rail to be supported evenly as far as possible at fixing points adjacent to each other and formed by systems of the type in question here. This concerns, on the one hand, the height positioning of the respective rail fixing point, but on the other hand also the height of the retaining force applied by the spring elements. In order to compensate for the irregularities, which are unavoidable in practice, in the evenness of the foundation on which the rail is mounted, support plates are arranged between rail foot and foundation, by means of which the rail is raised or lowered to the required level. At the same time, however, the respective guide plate retains its original position such that the relative position of rail foot and guide plate changes concomitantly with the height adjustment of the rail. This change influences the tension of the spring element supported on the guide plate and acting against the rail foot. As a result, when adjusting the height position of the rail, an unallowably high deviation of the retaining forces acting on adjacent fixing points can arise.

Against this background, the object of the invention was to create a system for fixing a rail, with which differences in the retaining force, which arise as a result of structural imprecisions of the foundation or adjustments in the height position of the rail that become necessary, can be compensated for in a simple manner. Likewise, a simple, cheap means was to be created, with which such compensation is possible in a problem-free manner.

In relation to the system for fixing a rail, this object was achieved by the invention in that such a system is formed in the manner given in claim 1.

With reference to the means for compensating differences in the retaining forces, according to the invention the solution to the task described above consists in the adapter piece given in claim 6.

Advantageous embodiments of the invention are given in the dependent claims and are explained below individually.

In a system according to the invention, the adapter piece used in the prior art as an isolator takes on the function of a compensation element, with which the forces applied to foot of the rail to be fixed by the respective spring element can be adjusted. For this purpose, the invention provides that the adapter piece is rotatably mounted on the end section of the spring arm of the spring element about a rotary axis and at the same time is provided at the periphery of the adapter piece with at least two contact surface sections, one of which, depending on the rotary position of the adapter piece, in each case lies against the rail foot. Here, one contact surface section of the adapter piece has a greater distance from the rotary axis of the adapter piece than the other contact surface section.

According to the invention, therefore, the adapter piece is formed and arranged on the spring arm of the spring element of a system according to the invention such that it can be adjusted in the manner of an eccentric element in order to set, with regard to pretension of spring element and force exerted by the spring element, the essential distance between the free end of the spring element and the surface of the rail foot. Thus the distance and with this the retaining force exerted by the spring element on the rail can be increased such that the adapter piece is supported on the rail foot via the contact surface section which has a great distance from the respective free end of the spring arm of the spring element. Consequently the effective retaining force can be reduced in that the adapter piece is turned so that it is supported on the rail foot via a contact surface section arranged at the smaller distance from the free end of the allocated spring arm.

An adapter piece intended for a system according to the invention for fixing a rail, which adapter piece has a holder in which an end section of a spring element can be inserted, is accordingly characterised in that at its periphery it has at least two contact surface sections, each one of which is provided, depending on the assembly position of the adapter piece, to lie on a rail foot of the respective rail to be fixed, and each one of which has a distance from the centre axis of the holder that differs from the distance of the respective other contact surface section from the centre axis of the holder.

With an adapter piece constructed according to the invention, it is therefore possible without any problems also to execute a height compensation between two adjacent fixing points for example by varying the height of the rail foot above the foundation or one of the other components of the respective support plate carrying the rail fixing system by means of one or more intermediate layers, wherein in this situation the guide plate supporting the respective spring element remains directly on the support plate or the foundation. The change, accompanying the height variation of the support of the rail foot, in the retaining force applied by the spring element in the finally assembled state onto the rail foot can likewise be compensated by a corresponding adjustment of the adapter piece.

Fundamentally, the contact surface sections of the adapter piece can have any desired form, as long as in the assembly position a secure fitting of the adapter on the rail foot and at the same time a likewise secure transfer of the retaining force are guaranteed. This is particularly simple to execute in that the contact surface sections are even in each case. The even embodiment of the contact surface sections not only has the advantage of a secure fitting and a likewise secure and widespread distribution of the retaining force on the rail foot, but also it allows a determined, clear adjustment value to be allocated to the respective contact surface section. Thus, for example, it is conceivable, proceeding from a starting value, to allow an increase in the height compensation achievable by the adapter by a fixed amount step-wise from contact surface section to contact surface section. This allows the fitter to undertake the necessary adjustments under often harsh on-site operating conditions in a problem-free manner, without also having to carry out numerous measurements. A particularly precise and at the same time simple-to-manage adjustment is therefore possible when the contact surface sections are adjacent to each other and separated in each case by an edge. Upon turning the adapter piece it is then clearly perceivable in each case when a change is made from one contact surface section to the other.

A further embodiment of the invention which is advantageous in practical use is characterised in that the adapter piece is elastic in its peripheral direction and the holder is smaller by a slight amount than the periphery of the end section of the spring arm allocated to it, so that in the assembly position the adapter piece is held on the end section of the spring arm of the spring element by form fit and friction fit. This embodiment allows, in a simple manner, a captive pre-assembly of the adapter piece on the spring arm respectively allocated to it. Furthermore, the friction fit between adapter piece and spring arm can be dimensioned such that the adapter piece, upon displacement from a pre-assembly position into a final assembled position, also securely retains its position in relation to the spring arm allocated to it even under the forces acting on it.

The positionally correct fixing of the adapter piece on the spring arm allocated to it can also be supported in that the holder of the adapter piece is formed as a blind-hole opening, in the base of which a passage opening is formed. In this case, the passage opening allows moisture entering the holder to escape, so that the danger of corrosion or frost damage occurring is effectively counteracted.

The elasticity, described above, of the adapter piece can be achieved in that a slot extending in the radial direction is formed in the peripheral wall limiting the holder. By means of this slot, upon insertion of the spring arm into the holder, the adapter piece is opened out in the manner of an annular spring, so that as a consequence of the resultant prevailing restoring forces the adapter piece is held by friction fit acting over the entire periphery of the end section of the spring arm sitting in the holder. Where the holder is formed as a blind-hole, the passage opening advantageously provided in the area of the base can be formed by the slot continuing into the base of the holder.

Fundamentally, the invention is suitable for every type of rail fixing, independently of whether a spring element with one or two spring arms is used for the generation of the retaining force. It has proved particularly advantageous, however, for the spring element to be an ω-shaped clamp with two spring arms and a respective adapter piece to be allocated to each of the spring arms. This not only allows a particularly simple assembly of the adapter pieces, but also an individual adjustment for each individual spring arm.

Naturally, in a system according to the invention, the adapter piece can electrically isolate the spring element from the rail foot. For this purpose, the adapter piece can be made for example from an electrically non-conductive material, in particular a plastic.

If, in a system according to the invention, it is to be ensured with particularly simple means that the adapter piece and with it the spring element coupled thereto securely retain their respective pre-assembly position even under the loads occurring in practice until final installation is performed, this can be achieved in that a guide plate is provided which has a contact surface on its face allocated to the rail foot and on its free top side a sliding surface limiting the contact surface and rising in the direction of the contact surface, via which the adapter piece can be moved from a pre-assembly position, established by a stop formed on the guide plate, in which it sits with its selected contact surface section on the guide plate, into an assembly position in which it sits with the contact surface section on the foot of the rail to be fixed, in order to transfer the elastic retaining force exerted by the spring element onto the rail foot. The spring element is also arranged on the guide plate, on which, to this end, forming elements are usually moulded which guide the spring element and secure its position.

In such a guide plate formed according to the invention, the adapter piece is pressed against the stop in the pre-assembly position as a result of the retaining force applied to it which is exerted by the spring element coupled to the adapter piece via the respective spring arm. In order to be moved into the final assembly position, the adapter piece must therefore be pushed, starting from the stop, obliquely upwards on the slide surface with the consequence that the spring forces exerted by the spring element increase and an additional force load must be overcome. As this cannot be achieved without targeted force applied externally, the adapter piece and with it the spring element are automatically held in the pre-assembly position until the final assembly process begins.

If, in a system according to the invention, it is to be possible to subsequently assemble or exchange a support plate for purposes of height regulation or improvement of the uniformity with which the loads taken up by the components of the system are distributed, this can be executed in a simple manner in that a support plate is provided, which extends transverse to the rail to be fastened over the width of the guide plate, and is arranged for adjustment of height differences between the foundation and the guide plate, wherein the support plate has a rectangular basic shape and features a passage opening for the clamping element for clamping the spring element, and wherein the support plate is divided into two parts along a joint line which is guided from the one long side of the support plate aligned transverse to the rail to be fixed, at a distance from the one short side to the passage opening and from there intersecting the passage opening in the direction of the short side of the support plate. The support plate provided in this embodiment is thus divided into two parts abutting each other, of which at least one part extends along the short side of the support plate over its entire width and on which a section extending in the longitudinal direction of the support plate is formed, which receives at least partly the passage opening for the clamping element concerned. The other part of the support plate fills the section cut out of the first part, limiting the part of the passage opening of the support plate which is not surrounded by the first part.

A first advantage of the design of a support plate according to the invention is that the two parts of the support plate can easily be mounted subsequently on an existing fixing system, in that viewed in the longitudinal direction of the rail one part is inserted from the one side and the other part from the other side below the other components of the fixing system already mounted. As soon as the two parts of the support plate are fully inserted, they closely surround the clamping element so that despite the division of the support plate, the same continuous support, over a large area, of the components and material layers resting on the support plate is guaranteed as with an undivided support plate.

A further advantage important in practice of the design of a support plate according to the invention is that it is undivided at least in the area of its one short side. In this way it is guaranteed that the components and material layers resting on the support can be securely supported even if very high pressures are exerted on the support plate or if the foundation has a degree of flexibility. The section of the one part of the support plate extending over the short side ensures that the support plate retains its form even under heavy load and its two parts cannot be pushed apart.

Additionally advantageous to the configuration according to the invention of a support plate is that both of its parts can be formed to be identical, whereby a cheap and simple manufacture is possible.

The invention is now explained below with reference to a drawing showing an exemplary embodiment in more detail. The drawings show schematically:

FIG. 1 a system for fixing a rail in an exploded view;

FIG. 2 the system in final assembled state in a perspective view;

FIG. 3 a support plate in a perspective view from above;

FIG. 4 the parts of the support plate in a perspective view from above;

FIG. 5 the parts of the support plate in a perspective view from below;

FIG. 6 a guide plate in a perspective view;

FIG. 7 the guide plate with adapter pieces thereon;

FIG. 8 an adapter piece in a front view;

FIG. 9 the adapter piece in a perspective view.

The system 1 for fixing a rail S on a solid foundation U formed for example by a concrete sleeper or concrete plate comprises a first support plate 2, a second support plate 3, an elastic intermediate layer 4, a pressure distribution plate 5, a height adjustment plate 6, a first guide plate 7, a second guide plate 8, two spring elements 9, 10 formed as ω-shaped clamps, two pairs of adapter pieces 11-14 and two clamping elements 15, 16 formed as clamping screws which act each via a washer 17, 18 on the centre loop of the spring elements 9, 10.

The fixing system 1 sits in a holder 19 moulded as one piece on the solid foundation U and limited on each of its short sides running parallel to rail S by a support shoulder 20, 21. In each contact surface of the holder 19 present between the support shoulders 20, 21 and adjacent to the support shoulders 20, 21, a plastic peg 22, 23 is inserted in the foundation U. Screwed into each plastic peg 22, 23 on assembly of the system 1 is one of the clamping elements 15, 16 to clamp the spring elements 9, 10.

The support plates 2, 3 each composed of two point-symmetrically shaped parts 24, 25 have a rectangular form with two parallel long sides 26, 27 and two likewise parallel short sides 28, 29, and extend over the entire width of the holder 19. In the support plates 2, 3 two passage openings 30, 31 are formed, each of which is positioned adjacent to one of the short sides 28, 29 and centrally between the long sides 26, 27 such that when the support plate 2, 3 is inserted in the holder 19, they align with the opening of the plastic peg 22, 23 inserted in the foundation U.

The joint line 32 at which the two parts 24, 25 of the support plates 2, 3 meet runs, starting from the edge of one long side 26, first parallel to the edge of the short side 28 allocated to the first passage opening 30, wherein the distance a1 from the edge concerned corresponds to the shortest distance between the edge of the passage opening 30 and the edge of the short side 28. This section 28 of the joint line is guided up to the passage opening 30 in order there to bend substantially at right angles to the edge of the short side 28 and to be guided, intersecting the passage opening 30 at its edge allocated to the long side 26, in the direction of the other passage opening 31. As soon as it has passed the passage opening 30, the joint line 32 bends in the direction of the other long side 27 so that it meets the passage opening 31 on its side allocated to the long side 27. There the joint line 32 again bends so that it runs substantially at right angles, intersecting the passage opening 31 at its edge allocated to the long side 27, to the edge of the other short side 29 until it has passed the passage opening 31. At this point the joint line 32 assumes a course aligned parallel to the edge of the short side 29 until it reaches the edge of the long side 27. The distance a2 of the section of the joint line 32 running parallel to the edge of the short side 29 corresponds to the smallest distance between the edge of the passage opening 31 and the edge of the short side 29.

With this course of joint line 32, the two parts 24, 25 of the support plate 2, 3 each have a section 33 extending over the entire width B of their short sides 28, 29. From this section 33 projects a further section 34 which in each case borders one of the long sides 26, 27 of the support plate 2, 3 concerned and the width of which in the area adjacent to section 33 corresponds to half the width B of the support plate plus half the diameter of the passage opening 30, 31 formed therein, whereas its width in the area of its free end is equal to half the width B of the respective support plate 2, 3 less half the diameter of the other passage opening 31, 30.

On the allocated ends of the parts 24, 25 of the support plates 2, 3, abutting in the joined state, correspondingly shaped protrusions and recesses 35, 36 are formed, which in the assembled state overlap each other by form fit and thus in the installation state prevent the parts 24, 25 from lifting in a direction perpendicular to the foundation U even under heavy load.

On each of the short sides 28, 29 of the support plates 2, 3 a shoulder 37, 38 is formed, which in the installation position are aligned pointing upwards away from sections 33, 34 and extend over the entire width B of the respective support plate 2, 3. The shoulders 37, 38 are formed and aligned such that they lie flush on the support shoulders 20, 21 in the state inserted in the holder 19.

To minimise their weight and save material, in the area of sections 33, 34 in the underside of parts 24, 25 regularly arranged recesses 39 are formed, between which ribs 40 are arranged, which in the installation state stand on the contact surface of the holder 19.

To achieve the height adjustment necessary in the present exemplary embodiment, the two support plates 2, 3 are arranged stacked on each other in the holder 19.

On any subsequent installation of the support plates 2, their parts 24, 25 are each pushed from one long side of the holder 19 below the other components of the system 1 until they abut each other and their protrusions and rebates 35, 36 engage. In this position the parts with their passage openings 30, 31 surround the screw shafts of the clamping elements 15, 16 with close tolerance so that despite the division of the support plates 2, 3, a maximum support area for the components of system 1 lying above them is guaranteed.

On the top support plate 3 lies the elastic intermediate layer 4 which guarantees the necessary flexibility of the rail fixing formed by the system 1.

The load absorbed by the rail S on passage of a rail vehicle not shown here is distributed over a large area onto the intermediate layer 4 by means of the pressure distribution plate 5 lying on the intermediate layer 4.

The intermediate layer 4 and the pressure distribution plate 5 each have slots on their short sides in which fit the clamping elements 15, 16 in the final assembled state.

The width of the intermediate layer 4 and the pressure distribution plate 5 is in each case less than the width B of the support plates 2, 3 so that along the long sides 26, 27 of the support plates 2, 3 is a short edge strip on which the guide plates 7, 8 stand with their side feet 41, 42 allocated to the rail foot F.

In order to compensate for any further height tolerances, on the pressure distribution plate 5 lies the height adjustment plate 6 on which the rail S stands with its rail foot F.

The guide plates 7, 8 made from a reinforced plastic are identical in structure. Each of them in the known manner is arranged on one of the long sides of the rail S in order to guide the rail S at the side. At the same time the guide plates 7, 8 also in a known manner serve as a bearing for the spring elements 9, 10 seated thereon.

On their face allocated to the rail foot F the guide plates 7, 8 have a contact surface 42 with which in the final mounted state they lie sideways against the rail foot F. The contact surface 42 in interrupted by two openings which lead to a recess 44 formed starting from the underside 43 of the guide plates 7, 8. In the area of the recess 44 reinforcing ribs not visible here are formed, which carry the roof 45 of the guide plates 7, 8 with spring elements 9, 10 clamped thereon.

At the side facing away from the contact surface 42, on these guide plates 7, 8 a support section 46 with recesses and reinforcement ribs is formed, on the free top side of which a flat support surface 47 is formed. On this support surface 47 in the pre-assembly position sit the transition sections of the spring elements 9, 10 which connect the spring arms 48, 49 of the spring elements 9, 10 with their centre loop. At the same time the support section 46 limits a channel 50 formed in the top of the guide plates 7, 8 and extending parallel to the contact surface 42, in which the transition sections of the spring elements 9, 10 sit in the final mounted position.

At a central point a passage opening 51 is formed in the roof 45 of the guide plates 7, 8, through which opening the screw shaft of the clamping element 15, 16 concerned is guided. The passage opening 51 is surrounded by a peripheral collar which firstly prevents the penetration of water into the opening 51 and secondly forms a guide for the central loop of the respective spring element 9, 10.

On both sides of the passage opening 51 and at an even distance from this on the top of the guide plate 7, 8 a step 52, 53 is formed, which reaches to the front contact surface 42. The steps 52, 53 in the final mounted system firstly form a side guide for the centre loop of the respective allocated spring element 9, 10. Secondly a wedge-shaped recess is formed in the steps 52, 53 starting from the top. In this way, at the end of the steps 52, 53 allocated to the support section 46, an upright stop 54, 55 and a flat slide surface 56, 57 are formed. These slide surfaces 56, 57 rise continuously starting from the stop 54, 55 in the direction of the contact surface 42 until they reach the front edge of the respective stop 52, 53 allocated to the contact surface 42.

Between the openings formed in the contact surface 42, a centre post 42 a is provided in the area of the contact surface 42, on the lower end of which post a protrusion 42 b is formed, directed away from the respective guide plate 8, 9 at right angles to the contact surface 42. The protrusion 42 b is positioned such that in the final mounted position it engages below the rail foot F. This safely prevents any lifting of the guide plates 8, 9 under the loads occurring in practice.

The spring elements 9, 10 formed as co-shaped clamps each have on their spring arms 48, 49 a cranked end section which, in the final mounted system 1, is aligned substantially parallel to the rail S. One of the adapter pieces 11-14 is mounted on each end section, pivoting about a rotary axis D coinciding with the long axis of the end section concerned.

Viewed from their front, the adapter pieces 11-14 have a pentagonal form. On the peripheral surface of the adapter pieces 11-14 three equal-sized contact surface sections 58, 59, 60 are formed, directly adjacent to each other and separated in each case by an edge 61, 62. Next to the two outer contact surface sections 58, 60 are two marking sections 63, 64. These marking sections 63, 64 can carry markings which indicate the increase or reduction in spring tension associated with rotation in the direction concerned.

The marker sections 63, 64 are separated by a slot 65 which is formed in the adapter pieces 11-14 from the radial direction and extends to a holder 66 formed in the adapter pieces 11-14 from the one front face. The slot 65 intersects a triangular opening 67 in the base 68 of the holder 66 so that any moisture or vapours collecting in the holder 66 can escape from the holder 66 via the opening 67.

The centre point M of the circular opening in the holder 66 is arranged offset in relation to the centre point of the faces 69 of the adapter pieces 11-14 so that the first contact surface section 58 has a first distance z1, the second contact surface section 59 a second distance z2 and the third contact surface section 60 a third distance z3 from the centre point M of the holder 66, where z1<z2<z3. Distances z1 to z3 each differ for example by one millimeter.

The adapter pieces 11-14 consist of an electrically non-conductive plastic which has a degree of elasticity at least in its peripheral direction.

In the relaxed state, not applied to the allocated end section of the spring arms 48, 49, the holder 66 of the adapter pieces 11-14 has a diameter which is smaller by a slight amount than the also largely circular end sections of the spring arms 48, 49. When the end sections are pushed into place, the adapter pieces 11-14 are spread accordingly in the peripheral direction so that as a result of the return forces acting in the adapter pieces 11-14, they are held on the allocated end section by friction fit but rotatable with a slight force application. The adapter pieces 11-14 can easily be spread because of the slot 65 which thus not only prevents the collection of moisture in the adapter pieces 11-14 concerned but also facilitates the placing of the adapter pieces 11-14 on the respective end section of the spring arms 48, 49 and ensures their adequate elastic flexibility.

For pre-mounting of the system 1, first the support plate 3 is laid in the holder 19 of the foundation U. Then the elastic layer 4 is placed on the support plate 2 and the pressure distribution plate 5 on the elastic layer.

The guide plates 8, 9 are then positioned so that in each case one of them lies with its support section 46 on one of the shoulders 37, 38 which again are each supported on one of the support shoulders 20, 21 of the foundation U. The guide plates 8, 9 with their side feet 41, 42 surround the intermediate layer 4 and the pressure distribution plate 5 so that they stand on the support plate 3. The centre post 42 a stands with its protrusion 42 b in the slot of the intermediate layer 4 and the pressure distribution plate 5.

Then on the pressure distribution plate 5 is placed the height adjustment plate 6, the width of which corresponds to the clear distance between the guide plates 7, 8.

Then the spring elements 9, 10 with adapter pieces 11-14 attached thereto are placed onto the allocated guide plates 7, 8 so that their transition section sits on the support surface 47 of the respective support section 46. In this position the adapter pieces 11-14 are placed with their contact surface section 58-60 allocated to the sliding surface 56, 57 concerned on the respective sliding surface 56, 57 and held resting on the respective stop 54, 55. Then after the clamping elements 15, 16 are screwed through the passage opening 51 of the respective angle guide plate 7, 8 and the passage openings 30, 31 of the support plate 2 into the allocated plastic peg 22, 23, the system 1 is provisionally clamped in its pre-assembly position.

After the rail S has been positioned, the spring elements 9, 10 are pushed in the direction of rail S until the adapter pieces 11-14 sit on their allocated side of the rail foot F and the transition sections of spring elements 9, 10 sit in the channel 50 of the guide plates 7, 8. The adapter pieces 11-14 then slide up the slide surfaces 56, 57 until they have passed the front free edge of steps 52, 53 and sit on the rail foot F.

If it is found that, as a result of excessive or too small a height difference between the top of the rail foot F and the top of the respective guide plate 7, 8, one of the spring elements 9, 10 exerts an inadequate or excessive retaining force on the rail foot F, this can be compensated by twisting the adapter piece 11-14 allocated to the spring element 9, 10 about its respective rotary axis D so that the adapter piece 11-14 concerned is supported on the rail foot F via a contact surface section 58, 59, 60 with a smaller distance (reduction of retention force) or a greater distance (increase in retention force) from the rotary axis D running through the centre point M of the holder 66.

The adapter pieces 11-14 thus allow very fine adjustment of the retaining forces applied by the spring elements 9, 10. At the same time they isolate the spring elements 9, 10 from the rail S.

If it is found that the height of the fixing point obtained by the system 1 for the rail S as a whole is too low, subsequently the additional support plate 2 and where applicable further support plates can be mounted below the support plate 3 in the manner already described above.

Reference numeral Designated element  1 System for fixing rail S  2, 3 Support plates  4 Elastic intermediate layer  5 Pressure distribution plate  6 Height adjustment plate  7, 8 Guide plates  9, 10 Spring elements 11-14 Adapter pieces 15, 16 Clamping elements 17, 18 Washers 19 Holder 20, 21 Support shoulders of holder 19 22, 23 Plastic peg 24, 25 Parts of support plates 2, 3 26, 27 Long sides of support plates 2, 3 28, 29 Short sides of support plates 2, 3 30, 31 Passage openings of support plates 2, 3 32 Joint line of support plate 2, 3 33, 34 Sections of parts 24, 25 35 Protrusions of parts 24, 25 36 Rebates of parts 24, 25 37, 38 Shoulders of parts 24, 25 39 Recesses of parts 24, 25 40 Ribs of parts 24, 25 41 Feet of guide plates 7, 8 42 Contact surface of guide plates 7, 8 42a Centre posts of guide plates 7, 8 42b Protrusion of guide plates 7, 8 43 Underside of guide plates 7, 8 44 Recess of guide plates 7, 8 45 Roof of guide plates 7, 8 46 Support section of guide plates 7, 8 47 Support surface of guide plates 7, 8 48, 49 Spring arms of spring elements 9, 10 50 Groove of guide plates 7, 8 51 Passage opening of guide plates 7, 8 52, 53 Step of guide plates 7, 8 54, 55 Stop of guide plates 7, 8 56, 57 Sliding surface of guide plates 7, 8 58, 59, 60 Contact surface sections of adapter pieces 11-14 61, 62 Edge of adapter pieces 11-14 63, 64 Marking sections of adapter pieces 11-14 65 Slot of adapter pieces 11-14 66 Holder of adapter pieces 11-14 67 Opening of adapter pieces 11-14 68 Base of adapter pieces 11-14 69 Front of adapter pieces 11-14 a1 Distance a2 Distance D Rotary axis of adapter pieces 11-14 F Rail foot M Centre point of holder 66 S Rail U Foundation z1, z2, z3 Distances 

1. System for fixing a rail onto a foundation comprising: a spring element, which can be clamped against the foundation by means of a clamping element, wherein the spring element has at least one spring arm; and an adapter piece, which has a holder, in which an end section of the spring arm of the spring element sits, wherein the adapter piece has a contact surface section formed at its periphery, with which, when the system is assembled, it sits on the rail foot of the rail to be fixed, such that the elastic retaining force exerted by the spring element is transferred onto the rail foot; and wherein the adapter piece is rotatably mounted on the end section of the spring arm about a rotary axis, such that the adapter piece has at its periphery at least two contact surface sections, one of which, depending on the rotary position of the adapter piece, in each case lies against the rail foot, and such that one contact surface section of the adapter piece has a greater distance from the rotary axis of the adapter piece than the other contact surface section.
 2. The system according to claim 1, wherein the spring element is an ω-shaped clamp with two spring arms and a respective adapter piece is allocated to each of the spring arms.
 3. The system according to claim 1, wherein the adapter piece electrically isolates the spring element from the rail foot.
 4. The system according to claim 1, comprising a guide plate, comprising a face allocated to the rail foot and a free top side, this face allocated to the rail foot having a contact surface, and the free top side having a sliding surface limiting the contact surface and rising in the direction of the contact surface, via which the adapter piece can be moved from a pre-assembly position, established by a stop formed on the guide plate, in which it sits with its selected contact surface section on the guide plate, into an assembly position in which it sits with the contact surface section on the rail foot of the rail to be fixed, in order to transfer the elastic retaining force exerted by the spring element onto the rail foot.
 5. The system according to claim 1, wherein a support plate is provided which extends transverse to the rail to be fixed over the width of the guide plate; the support plate is arranged to compensate for height differences between the guide plate and a foundation; the support plate has a rectangular base form and comprises a passage opening for the clamping element used for clamping the spring element; and the support plate is divided into two parts along a joint line which is guided from a long side of the support plate aligned transverse to the rail to be fixed, at a distance from a short side to a passage opening and from there intersecting the passage opening in the direction of the short side of the support plate.
 6. An adapter piece for a system formed according to claim 1, comprising a holder in which an end section of the spring arm of the spring element can be inserted, wherein the adapter piece at its periphery has at least two contact surface sections, each one of which is provided, depending on the assembly position of the adapter piece, to lie on a rail foot of the respective rail to be fixed, and each one of which has a distance from the centre axis of the holder that differs from the distance of the respective other contact surface section from the centre axis of the holder.
 7. The adapter piece according to claim 6, wherein the contact surface sections are even in each rotary position of the adapter piece.
 8. The adapter piece according to claim 6, wherein the contact surface sections are adjacent to each other and separated in each rotary position of the adapter piece by an edge.
 9. The adapter piece according to claim 6, wherein the adapter piece is elastic in its peripheral direction and the holder of the adapter piece is smaller by a slight amount than the periphery of the end section of the spring arm of the spring element allocated to it, such that in the assembly position the adapter piece is held on the end section of the spring arm of the spring element by form fit and friction fit.
 10. The adapter piece according to claim 6, wherein the holder of the adapter piece is formed as a blind-hole opening, in the base of which a passage opening is formed.
 11. The adapter piece according to claim 9, wherein a slot extending in the radial direction is formed in the peripheral wall limiting the holder.
 12. The adapter piece according to claim 11, wherein the slot continues into the base of the holder and forms the passage opening in the area of the base. 